By default Linux operating system use more RAM memory for disk cache, because of reading data from cache if more faster than reading data from hard drive, we can clear cached on your system and this is a non-destruction operation,

If you want to be merge two line set to one, SED and AWK command can use for this.

We have already discussed about find and replace a line or specific word in simple commands using SED.

If you are using Dedicated server or Virtual private server, files or directories access,modify,changes,logs reports time based on your timezone settings.

Linux-Unix operating systems is logged system activities some one place. This post describe about how to get know last logged and log out, shutdown time, system reboot time from the logs. This information stored in wtmp and btmp file.

Set the ownership and permission for a file using chown and chmod command, If you want to Clone ownership and permissions from another file.

Can see the serial or model number of your hard disks from the terminal, the below commands are get information lshw, lsblk, hdparm, smartctl, palimpsest.